Well, like I said to "bobpaul" in a private message, when I first ran into trouble with Kubuntu booting, I disabled the "quiet" mode so I could read what the kernel was printing since I have some familiarity with the Linux kernel and have done some troubleshooting with it in the Red Hat environment. Every time I tried to boot it, it kept hanging when it would get to the hard disk initialization stuff. From what I gathered from going through the Ubuntu forums, it appears they decided to switch over to that new ATA driver ("libata" I think) that apparently makes every drive in the system look like a SCSI drive (all /dev/sdx instead of /dev/hdx and /dev/sdx). I have only a parallel ATA drive installed on the target system, so it could not have been recognizing any serial ATA drive I had in there. Regardless, it just wouldn't talk to my PATA hard disk under any circumstances with this driver whereas RHEL, using the "tried and true" older drivers, works just fine with it and doesn't complain.
I eventually gave up and just decided to try to get things going with Red Hat and MythTV on this system since the pcHDTV card works fine and I can get that working.
The previous version of Ubuntu/Kubuntu would boot fine, but obviously that won't let me run the newest version of LinuxMCE and I don't want to download the 1.00 release if it'll be a "dead end" (particularly if something doesn't work for me that is fixed by one of the beta releases).